Passenger counting device, system, method and program

ABSTRACT

The image processing system acquires a first image which includes a target object illuminated by both of a first light and a second light, the second light being generated by a light source that emit light in a specific wavelength band, and an external object illuminated by the first light but not illuminated by the second light. The system acquires a second image generated by photographing a range same as a range of the first image through a filter causing wavelength distribution of observed light for the second image to be different from wavelength distribution of observed light for the first image. The system generates a third image in which intensity of a figure of the external object is raised as compared to the first image; and a fourth image in which intensity of a figure of the external object is reduced as compared to the first image.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.15/572,995, filed Nov. 9, 2017, now U.S. Pat. No. 10,318,830, which is aNational Stage of International Application No. PCT/JP2016/001557 filedMar. 17, 2016, the disclosures of which are incorporated herein in theirentirety by reference.

TECHNICAL FIELD

The present invention relates to passenger counting device, system,method, and program to count the number of passengers of a vehicle.

BACKGROUND ART

In recent years, a high occupancy vehicle (HOV) system, which discountstolls depending on the number of passengers of a vehicle or permitspassage of a road only to a vehicle with the passenger number exceedinga predetermined number, has been used. In the HOV system, a technique isused in which the passenger number is counted by photographing a vehicleusing a camera and performing face detection on the photographed image.

PTLs 1 to 3 disclose a system for counting the number of passengers of avehicle by face detection. PTL 1 discloses a technique of counting thenumber of passengers of a vehicle by detecting a profile of a person.PTL 2 discloses a technique of measuring the passenger number bydetecting persons and estimating at which positions in a vehicle thepersons are on board. PTL 3 discloses a technique of counting thepassenger number using a movement amount of a vehicle and a persondetection result.

CITATION LIST Patent Literature

PTL 1: International Publication No. 2014/061195

PTL 2: International Publication No. 2014/064898

PTL 3: International Publication No. 2015/052896

SUMMARY OF INVENTION Technical Problem

There is a case where a person or an object outside a vehicle isreflected on a window of the vehicle in an image obtained byphotographing the vehicle. In such a case, there is a possibility oferroneous detection at the time of performing face detection for aperson inside the vehicle due to the reflection of the window of thevehicle in the acquired image.

Accordingly, an object of the present invention is to provide passengercounting device, system, method and program capable of accuratelycounting the number of passengers of a vehicle.

Solution to Problem

A passenger counting device according to the present invention ischaracterized by including: an image separation means for acquiring aplurality of separate images based on a first image acquired byphotographing a vehicle and a second image acquired by photographing thevehicle in a state of receiving only light of a first specificwavelength band; and a passenger number determination means fordetermining the number of passengers of the vehicle based on theplurality of separate images.

A passenger counting system according to the present invention ischaracterized by including: a first photographing means forphotographing a vehicle and acquiring a first image; a secondphotographing means for photographing the vehicle in a state ofreceiving only light of a first specific wavelength band and acquiring asecond image; an image separation means for acquiring a plurality ofseparate images based on the first image and the second image; and apassenger number determination means for determining the number ofpassengers of the vehicle based on the plurality of separate images.

A passenger counting method according to the present invention ischaracterized by acquiring a plurality of separate images based on afirst image acquired by photographing a vehicle and a second imageacquired by photographing the vehicle in a state of receiving only lightof a first specific wavelength band and determining the number ofpassengers of the vehicle based on the plurality of separate images.

A passenger counting program according to the present invention ischaracterized by causing a computer to execute: an image separationprocess of acquiring a plurality of separate images based on a firstimage acquired by photographing a vehicle and a second image acquired byphotographing the vehicle in a state of receiving only light of a firstspecific wavelength band; and a passenger number determination processof determining the number of passengers of the vehicle based on theplurality of separate images.

Advantageous Effects of Invention

According to the present invention, it is possible to accurately countthe number of passengers of the vehicle.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 It depicts a block diagram illustrating a configuration of afirst exemplary embodiment of a passenger counting system according tothe present invention.

FIG. 2 It depicts a block diagram illustrating a hardware configurationof the first exemplary embodiment of the passenger counting systemaccording to the present invention.

FIG. 3 It depicts a flowchart illustrating an operation of the firstexemplary embodiment of the passenger counting system according to thepresent invention.

FIG. 4 It depicts an explanatory view illustrating a first imageacquired by a first photographing unit.

FIG. 5 It depicts an explanatory view illustrating a separate imageaccording to the first exemplary embodiment.

FIG. 6 It depicts a block diagram illustrating a configuration of asecond exemplary embodiment of the passenger counting system accordingto the present invention.

FIG. 7 It depicts a block diagram illustrating a hardware configurationof the second exemplary embodiment of the passenger counting systemaccording to the present invention.

FIG. 8 It depicts a flowchart illustrating an operation of the secondexemplary embodiment of the passenger counting system according to thepresent invention.

FIG. 9 It depicts an explanatory view illustrating a separate imageaccording to the second exemplary embodiment.

FIG. 10 It depicts a flowchart illustrating an operation of a thirdexemplary embodiment of the passenger counting system according to thepresent invention.

FIG. 11 It depicts a schematic block diagram illustrating aconfiguration example of a computer to which a passenger counting deviceaccording to the present invention is mounted.

FIG. 12 It depicts a block diagram illustrating a configuration of amain part of the passenger counting system according to the presentinvention.

DESCRIPTION OF EMBODIMENTS First Exemplary Embodiment

A configuration of a passenger counting system according to the presentexemplary embodiment will be described with reference to FIGS. 1 and 2.FIG. 1 is a block diagram illustrating the configuration of thepassenger counting system according to the present exemplary embodiment.The passenger counting system includes a first photographing unit 10, asecond photographing unit 11, and a passenger number counting device100. In addition, the passenger counting device 100 includes an imageseparation unit 12 and a passenger number determination unit 13.

The first photographing unit 10 photographs a vehicle and acquires afirst image. The first photographing unit 10 is a general camera, andphotographs the vehicle as a subject to generate a digital image.

The second photographing unit 11 photographs the vehicle in a state ofreceiving only a first specific wavelength band and acquires a secondimage. The second photographing unit 11 is a general camera similar tothe first photographing unit 10, and photographs the vehicle as thesubject to generate a digital image. The second photographing unit 11has sensitivity of light of at least the first specific wavelength band.

The image separation unit 12 performs image separation based on thefirst image acquired by the first photographing unit 10 and the secondimage acquired by the second photographing unit 11, thereby acquiring aplurality of separate images including a separate image in whichreflection on a glass window is reduced. Specifically, the imageseparation unit 12 separates image data into two images having differentdistances from the first photographing unit 10 and the secondphotographing unit 11 using independent component analysis.

The passenger number determination unit 13 determines the number ofpassengers of the vehicle based on the plurality of separate imagesoutput by the image separation unit 12. Specifically, the passengernumber determination unit 13 acquires the plurality of separate imagesoutput by the image separation unit 12, performs face detection on theseparate image in which the reflection is reduced, and determines thenumber of parts, which have been determined as a face of a person, asthe number of passengers of the vehicle.

FIG. 2 is an explanatory diagram illustrating a hardware configurationof the passenger counting system according to the present exemplaryembodiment. The first photographing unit 10 and the second photographingunit 11 are installed at positions, such as a road side, where thevehicle can be photographed. A half mirror 20 is installed in front ofthe first photographing unit 10 (between the first photographing unit 10and the vehicle). A reflection mirror 21 is installed in front of thesecond photographing unit 11 (a position receiving reflected light fromthe half mirror 20). In addition, a band-pass filter 22 is installedbetween the second photographing unit 11 and the reflection mirror 21.The band-pass filter 22 is a filter that can pass only light of a firstspecific wavelength band λ₁.

A part of light incident from a direction of the vehicle passes throughthe half mirror 20 and is incident on the first photographing unit 10.In addition, the remaining part of the light incident from the directionof the vehicle is reflected by the half mirror 20 and is incident on thereflection mirror 21. The light incident on the reflection mirror 21 isreflected and passes through the band-pass filter 22, and only the lightof the first specific wavelength body λ₁ is incident on the secondphotographing unit 11.

In the configuration illustrated in FIG. 2, the respective devices areinstalled such that an optical path length from the first photographingunit 10 to the vehicle and an optical path length from the secondphotographing unit 11 to the vehicle are the same. In addition, thefirst photographing unit 10 and the second photographing unit 11 performphotographing such that a photographing range of the first photographingunit 10 and a photographing range of the second photographing unit 11are the same.

In addition, a lamp 23 that emits the light of the first specificwavelength band λ₁ is installed at a position where a passing vehiclecan be irradiated to irradiate the entire vehicle. As the light passesthrough the band-pass filter 22, the light quantity decreases ascompared with the light quantity before passing. However, the secondphotographing unit 11 can obtain the sufficient light quantity as thelamp 23 irradiates the vehicle with the light of the first specificwavelength band λ₁, and thus, it is possible to acquire a clear vehicleimage.

With the above-described configuration, the first photographing unit 10can photograph a normal vehicle image in a state where a wavelength ofincident light is not limited. The second photographing unit 11 canphotograph a vehicle image in a state where only the light of the firstspecific wavelength band λ₁ is incident.

Next, an operation of the passenger counting system according to thepresent exemplary embodiment will be described. FIG. 3 is a flowchartillustrating the operation of the passenger counting system according tothe present exemplary embodiment.

The first photographing unit 10 photographs the vehicle and acquires theimage (step S10). The first photographing unit 10 is installed on theroad side, for example, and photographs the vehicle from a lateraldirection (a direction perpendicular to a traveling direction of thevehicle).

The second photographing unit 11 photographs the vehicle in the state ofreceiving only the light of the first specific wavelength band andacquires the image (step S11). The second photographing unit 11 isinstalled on the road side, for example, and photographs the vehiclefrom the lateral direction (the direction perpendicular to the travelingdirection of the vehicle), which is similar to the first photographingunit 10. Since the band-pass filter 22 is installed in front of thesecond photographing unit 11, the second photographing unit 11photographs the vehicle in the state where only the light of the firstspecific wavelength body λ₁ is incident.

However, the installation positions of the first photographing unit 10and the second photographing unit 11 are not limited to theabove-described positions, and may be set to positions that enablephotographing from the front or diagonally front of the vehicle. Forexample, the first photographing unit 10 and the second photographingunit 11 are installed at a tollgate that utilizes an HOV system.

The first photographing unit 10 and the second photographing unit 11photograph the vehicle at the same timing. For example, the passengercounting device 100 transmits an instruction signal to the firstphotographing unit 10 and the second photographing unit 11 in order tosynchronize photographing timings. For example, a detection means suchas an infrared sensor is installed in order to detect a timing ofpassing of the vehicle, and the passenger counting device 100 maytransmit an indication signal to the first photographing unit 10 and thesecond photographing unit 11 at a timing of receiving a signalindicating that the vehicle has passed from the detection means.Alternatively, the first photographing unit 10 and the secondphotographing unit 11 may directly receive the signal indicating thatthe vehicle has passed from the detection unit, and performphotographing at the timing of receiving the signal.

The image separation unit 12 performs the image separation based on thefirst image obtained by photographing the vehicle through the firstphotographing unit 10 and the second image obtained by photographing thevehicle through the second photographing unit 11, and acquires theplurality of separate images including the separate image in which thereflection on the glass window is reduced (step S12). Specifically, theimage separation unit 12 performs the independent component analysis onimage data representing the first image and the second image, andseparates an image representing the interior of the vehicle from animage representing the reflection on the glass window (a person, anobject, or the like reflected on the glass window).

The image separation using the independent component analysis will bedescribed in details. Image data representing the first image is denotedby x₁, and image data representing the second image is denoted by x₂. Inaddition, an actual image representing the interior of the vehicle isdenoted by s₁, and an actual image representing the reflection on theglass window is denoted by s₂. Then, the acquired image is denoted by avector X=(x₁, x₂)^(T), and the actual image is denoted by a vectorS=(s₁, s₂)^(T). Since the image data x₁ and x₂ are obtained in the stateof mixing of s₁ and s₂, the following Formula (1) is established when amixing matrix is A.X=AS  (1)

Since A is an unknown matrix, it is necessary to estimate S from X. Theimage separation unit 12 estimates y₁ and y₂ by calculating a matrix Wsuch that y₁ and y₂ of the vector Y=(y₁, y₂) are independent in thefollowing Formula (2).Y=WX  (2)

As described above, one of y₁ and y₂, obtained by the processing asdescribed above, is an approximate value of s₁ representing the interiorof the vehicle, and the other is an approximate value of s₂ representingthe reflection on the glass window. The image separation unit 12 outputsthe image data which is the approximate value of s₁ representing theinterior of the vehicle between y₁ and y₂ representing the image data asthe separate image in which the reflection is reduced. For example, theimage separation unit 12 analyzes the images of y₁ and y₂ and determineswhether or not the image is an image inside the vehicle depending onpresence or absence of a face of a person or in-vehicle equipment.Alternatively, the image separation unit 12 may output the imagesrepresented by y₁ and y₂ to an external display device to allow a userto select which image is the image inside the vehicle, and output theselected image as the separate image in which the reflection is reduced.In addition, the image separation unit 12 may determine which image isthe image in which the reflection is reduced using a specific method,and output the determined image as the separate image in which thereflection is reduced. Specifically, the image separation unit 12applies an algorithm to detect a face to the images represented by y₁and y₂, and acquires the number of faces. Thereafter, the imageseparation unit 12 may select and output an image having the largernumber of faces as the separate image in which the reflection isreduced. Here, there is no particular need to be limited to the numberof faces, any part may be used as long as it is a detectable part of aperson, and a nose, an eye, an arm, a neck, or the like can be also usedas a detection target. Incidentally, the passenger counting device 100may include a selection means for selecting an image in which reflectionis reduced from among the plurality of separate images, and anacquisition means for acquiring the number of specific parts of a personfor the plurality of separate images, in addition to the imageseparation unit 12.

FIG. 4 is an explanatory view illustrating the first image acquired bythe first photographing unit 10. FIG. 5 is an explanatory viewillustrating the separate image in the present exemplary embodiment. Inthe image illustrated in FIG. 4, a tree outside the vehicle is reflectedon the glass window of the vehicle and is displayed to be superimposedon the face of the person inside the vehicle. In the separate imageillustrated in FIG. 5, the reflection on the glass window is reduced,and the face of the person inside the vehicle is clearly displayed.Although not illustrated, the reflection on the glass window isdisplayed in the other image obtained by separation. That is, image datais separated into two images having different distances from the firstphotographing unit 10 and the second photographing unit 11 based on thefirst image and the second image.

The passenger number determination unit 13 determines the number ofpassengers of the vehicle based on the plurality of separate imagesoutput by the image separation unit 12 (step S13). Specifically, thepassenger number determination unit 13 acquires the plurality ofseparate images output by the image separation unit 12, performs facedetection on the separate image in which the reflection is reduced, anddetermines the number of parts, which have been determined as the faceof the person, as the number of passengers of the vehicle.

When the face of the passenger is reflected at an angle close to aprofile, the passenger number determination unit 13 detects the personusing a profile detector. Alternatively, when the face of the passengeris reflected at an angle close to a front face, the passenger numberdetermination unit 13 detects the person using a front face detector.These detectors are constructed, in advance, by performing machinelearning using a large number of face images photographed from the sideor the front, and are stored in a storage unit (for example, anauxiliary storage device 1003 to be described later). The detector usedfor detection is, for example, a detector obtained by support vectormachine (SVM), latent dirichlet allocation (LDA), and generalizedlearning vector quantization (GLVQ).

As described above, the passenger counting system according to thepresent exemplary embodiment can reduce the reflection on the glasswindow of the vehicle by performing the image separation using theindependent component analysis, and thus, can accurately count thenumber of passengers of the vehicle.

Second Exemplary Embodiment

A passenger counting system according to the present exemplaryembodiment will be described with reference to the drawings.Incidentally, content of the following description mainly relates toconfigurations and functions different from those of the first exemplaryembodiment (Exemplary Embodiment 1), and configurations and functionswhich are not particularly described are assumed to be the same as thoseof the first exemplary embodiment. FIG. 6 is a block diagramillustrating a configuration of the passenger counting system accordingto the present exemplary embodiment. The passenger counting systemincludes a first photographing unit 10, a second photographing unit 11,a third photographing unit 14, and a passenger number counting device100. In addition, the passenger counting device 100 includes an imageseparation unit 12 and a passenger number determination unit 13. Thepassenger counting system according to the present exemplary embodimentis configured by adding the third photographing unit 14 to the passengercounting system according to the first exemplary embodiment.

The third photographing unit 14 photographs a vehicle in a state ofreceiving only a second specific wavelength band different from a firstspecific wavelength band and acquires a third image. The thirdphotographing unit 14 is a general camera similar to the firstphotographing unit 10 and the second photographing unit 11, andphotographs the vehicle as a subject to generate a digital image. Thethird photographing unit 14 has sensitivity of light of at least thesecond specific wavelength band.

FIG. 7 is an explanatory diagram illustrating a hardware configurationof the passenger counting system according to the present exemplaryembodiment. The third photographing unit 14 is installed at a positionwhere the vehicle can be photographed. A band-pass filter 26 isinstalled in front of the third photographing unit 14. The band-passfilter 26 is a filter that can pass only light of a second specificwavelength band 2. A half mirror 25 is installed in front of the firstphotographing unit 10. A part of the light incident on the half mirror25 from a direction of the vehicle is reflected and incident on areflection mirror 27. The light incident on the reflection mirror 27 isreflected, passes through the band-pass filter 26, and is incident onthe third photographing unit 14. In addition, a lamp 24 that emits thelight of the second specific wavelength band λ₂ is installed at aposition where the vehicle can be irradiated to irradiate the entirevehicle. The other configurations are the same as those of the firstexemplary embodiment, and thus, the description thereof will be omitted.

In the configuration illustrated in FIG. 7, the respective devices areinstalled such that an optical path length from the first photographingunit 10 to the vehicle, an optical path length from the secondphotographing unit 11 to the vehicle, and an optical path length fromthe third photographing unit 14 to the vehicle are the same. Inaddition, the first photographing unit 10, the second photographing unit11, and the third photographing unit 14 perform photographing such thata photographing range of the first photographing unit 10, aphotographing range of the second photographing unit 11, and aphotographing range of the third photographing unit 14 are the same.

With the above-described configuration, the third photographing unit 14can photograph a vehicle image in the state where only the light of thesecond specific wavelength body λ₂ is incident. As the light passesthrough the band-pass filter 26, the light quantity decreases. However,the third photographing unit 14 can obtain a sufficient light quantityas the lamp 24 irradiates the vehicle with the light of the secondspecific wavelength band 2, and thus, it is possible to acquire theclear vehicle image.

Next, an operation of the passenger counting system according to thepresent exemplary embodiment will be described. FIG. 8 is a flowchartillustrating the operation of the passenger counting system according tothe present exemplary embodiment. Incidentally, the processes in stepsS10, S11, and S13 illustrated in FIG. 8 are the same as those in thefirst exemplary embodiment, and thus, the description thereof will beomitted.

The third photographing unit 14 photographs the vehicle in the state ofreceiving only the light of the second specific wavelength band andacquires the image (step S11′). The installation position of the thirdphotographing unit 14 may be any position as long as it is the positionat which the vehicle can be photographed, which is similar to theinstallation positions of the first photographing unit 10 and the secondphotographing unit 11 that have been described in the first exemplaryembodiment. The third photographing unit 14 is installed on the roadside, for example, and photographs the vehicle from a lateral direction(direction perpendicular to a traveling direction of the vehicle). Sincethe band-pass filter 26 is installed in front of the third photographingunit 14, the third photographing unit 14 photographs the vehicle in thestate where only the light of the second specific wavelength body λ₂ isincident. In addition, the third photographing unit 14 photographs thevehicle at the same timing as the first photographing unit 10 and thesecond photographing unit 11.

The image separation unit 12 performs the image separation based on afirst image acquired by photographing the vehicle through the firstphotographing unit 10, a second image acquired by photographing thevehicle through the second photographing unit 11, and the third imageacquired by photographing the vehicle through the third photographingunit 14, and acquires a plurality of separate images in which reflectionon a glass window and depth of a vehicle body portion of the vehicle arereduced (step S12′). Specifically, the image separation unit 12 performsindependent component analysis on image data representing the firstimage, the second image, and the third image, and separates an imagerepresenting the interior of the vehicle, an image representing thereflection on the glass window (a person, an object, or the likereflected on the glass window), and a part of the vehicle except for theglass window (hereinafter, referred to as the vehicle body portion).

The image separation using the independent component analysis will bedescribed in details. Image data representing the first image is denotedby x₁, image data representing the second image is denoted by x₂, andimage data representing the third image is denoted by x₃. In addition,an actual image representing the interior of the vehicle is denoted bys₁, an actual image representing the reflection on the glass window isdenoted by s₂, and an actual image representing the vehicle body portionof the vehicle is denoted by s₃. Then, the acquired image is denoted bya vector X=(x₁, x₂, x₃)^(T), and the actual image is denoted by a vectorS=(s₁, s₂, s₃)^(T). Since the image data x₁, x₂, and x₃ are obtained inthe state of mixing of s₁, s₂, and s₃, the Formula (1) is establishedwhen a mixing matrix is A, which is similar to the first exemplaryembodiment.

The image separation unit 12 calculates a vector Y in Formula (2). Inthe present exemplary embodiment, it is expressed as the vector Y=(y1,y2, y3). The image separation unit 12 estimates y1, y2, and y3 bycalculating a matrix W such that y1, y2, and y3 are independent.

One of y₁, y₂, and y₃ obtained as described above is an approximatevalue of s₁ representing the interior of the vehicle, another one is anapproximate value of s₂ representing the reflection on the glass window,and the other one is an approximate value of s₃ representing the vehiclebody portion of the vehicle. The image separation unit 12 outputs theimage data which is the approximate value of s₁ representing theinterior of the vehicle among y₁, y₂, and y₃ that represent the imagedata as a separate image in which the reflection and the depth of thevehicle body portion of the vehicle are reduced. For example, the imageseparation unit 12 analyzes the images of y₁, y₂, and y₃ and determineswhether or not the image is an image inside the vehicle depending onpresence or absence of a face of a person or in-vehicle equipment.Alternatively, the image separation unit 12 may output the imagesrepresented by y₁, y₂, and y₃ to an external display device to allow auser to select which image is the image inside the vehicle, and outputthe selected image as the separate image in which the reflection and thedepth of the vehicle body portion of the vehicle are reduced.

FIG. 9 is an explanatory view illustrating the separate image accordingto the present exemplary embodiment. In the separate image illustratedin FIG. 9, the reflection on the glass window is reduced, and the faceof the person inside the vehicle is clearly displayed. Further, thedepth of the main body part of the vehicle is reduced. Although notillustrated, the reflection on the glass window and the main body partof the vehicle are displayed, respectively, on the other images obtainedby separation.

When the image of the vehicle includes the vehicle body portion, it ispreferable that the user perform image processing to eliminate thevehicle body portion of the vehicle in advance before performing facedetection. However, the vehicle body portion of the vehicle has alreadybeen removed from the separate image according to the present exemplaryembodiment as illustrated in FIG. 9. Thus, the passenger numberdetermination unit 13 can accurately determine the number of passengersin a process of performing the face detection and determining the numberof passengers of the vehicle.

As described above, the passenger counting system according to thepresent exemplary embodiment can reduce not only the reflection on theglass window of the vehicle but also the depth of the vehicle bodyportion of the vehicle by performing the image separation using theindependent component analysis. Thus, it is possible to accurately countthe number of passengers of the vehicle even if the user does notperform the image processing to remove the vehicle body portion of thevehicle according to the passenger counting system of the presentexemplary embodiment.

Third Exemplary Embodiment

A passenger counting system according to the present exemplaryembodiment will be described with reference to the drawings. In thepresent exemplary embodiment, only a function of the passenger numberdetermination unit 13 is different from that of the first exemplaryembodiment, and the other configurations are the same, and thus, thedescription of the configuration will be omitted. It is assumed that theconfigurations and functions that are not specifically described are thesame as those in the first exemplary embodiment.

FIG. 10 is a flowchart illustrating an operation of the passengercounting system according to a third exemplary embodiment. In FIG. 10,steps S10 to S12 are the same as the processes of the first exemplaryembodiment (see FIG. 3), and thus, the description thereof will beomitted.

Although the passenger number determination unit 13 acquires theplurality of separate images output by the image separation unit 12,there is a case where it is difficult to determine any separate imagethat is the separate image in which the reflection is reduced. Thus, thepassenger number determination unit 13 performs a face detection processon all the acquired separate images, and acquires the number ofpassengers in each separate image (step S13 a).

Then, the passenger number determination unit 13 determines a maximumvalue among the number of passengers of each separate image as theactual number of passengers (step S13 b).

Although the image separation unit 12 determines any separate image thatis the separate image in which the reflection is reduced or performs theprocess of causing the user to select the separate image in the firstexemplary embodiment, these processes may be omitted in the presentexemplary embodiment.

Although the example in which the passenger number determination unit 13of the passenger counting system according to the first exemplaryembodiment is changed is illustrated in the present exemplaryembodiment, the passenger number determination unit 13 according to thepresent exemplary embodiment may be applied to the configuration of thepassenger counting system according to the second exemplary embodiment.

According to the passenger counting system of the present exemplaryembodiment, it is possible to accurately determine the number ofpassengers even when it is difficult to determine any separate imagethat is the separate image in which the reflection is reduced.

FIG. 11 is a schematic block diagram illustrating a configurationexample of a computer according to the present exemplary embodiment. Acomputer 1000 includes a CPU 1001, a main storage device 1002, anauxiliary storage device 1003, an interface 1004, a display device 1005,and an input device 1006.

The passenger counting device 100 according to the present exemplaryembodiment is mounted to the computer 1000. The passenger numbercounting device 100 is stored in the auxiliary storage device 1003 inthe form of a program. The CPU 1001 reads out the program from theauxiliary storage device 1003 and expands the program into the mainstorage device 1002 to execute the above-described processes accordingto the program.

The auxiliary storage device 1003 is a non-transitory tangible medium,and for example, is a magnetic disk, a magneto-optical disk, a CD-ROM, aDVD-ROM, a semiconductor memory, or the like. The computer 1000 may beconnected to the auxiliary storage device 1003 via the interface 1004.When the program is distributed to the computer 1000 via a communicationline, the computer 1000 may expand the program into the main storagedevice 1002 and execute the above-described processes in response to thedistribution.

In addition, the program may be configured to implement some of theabove-described processes. Further, the program may be a differentialprogram which implements the above-described processes in combinationwith other programs that have been already stored in the auxiliarystorage device 1003. In addition, a processor included in the computer1000 is not limited to the CPU 1001, and it may be enough to provide aprocessor capable of executing a program. In addition, the computer 1000includes a circuit.

FIG. 12 is a block diagram illustrating a main part of the passengercounting system according to the present invention. The passengercounting system according to the present invention includes: a firstphotographing means 30 for photographing a vehicle and acquiring a firstimage; a second photographing means 31 for photographing the vehicle ina state of receiving only light of a first specific wavelength band andacquiring a second image; and a passenger counting device 200. Thepassenger counting device 200 includes: an image separation means 42 foracquiring a plurality of separate images based on the first image andthe second image; and a passenger number determination means 43 fordetermining the number of passengers of the vehicle based on theplurality of separate images.

In addition, the passenger counting system illustrated in the following(1) to (7) is also disclosed in the above-described exemplaryembodiments.

(1) The passenger counting system may be configured such that thepassenger counting means (for example, the passenger numberdetermination unit 13) acquires the number of passengers for each of theplurality of separate images and determines the maximum value of theacquired number of passengers as the number of passengers of thevehicle.

(2) The passenger counting system may be configured such that the imageseparation means (for example, the image separation unit 12) performsimage separation using the independent component analysis. According tosuch a passenger counting system, it is possible to execute the imageseparation only from the first image and the second image.

(3) The passenger counting system may be configured such that the imageseparation means (for example, the image separation unit 12) separatesimage data into two images having different distances from the firstphotographing means (for example, the first photographing unit 10) andthe second photographing means (for example, the second photographingunit 11) based on the first image and the second image.

(4) The passenger counting system may be configured to include theirradiation means (for example, the lamp 23) for irradiating the vehiclewith the light of the first specific wavelength band. According to sucha passenger counting system, it is possible to compensate for thedecrease in the light quantity even in the state of receiving only thelight of the first specific wavelength band.

(5) The passenger counting system may be configured such that theoptical path length from the first photographing means to the vehicleand the optical path length from the second photographing means to thevehicle are the same.

(6) The passenger counting system may be configured such that thephotographing range of the first photographing means and thephotographing range of the second photographing means are the same.

(7) A passenger counting system including: the first photographing means(for example, the first photographing unit 10) for photographing thevehicle and acquiring the first image; the second photographing means(for example, the second photographing unit 11) for photographing thevehicle in the state of receiving only the light of the first specificwavelength band and acquiring the second image; the third photographingmeans (for example, the third photographing unit 14) for photographingthe vehicle in the state of receiving only the light of the secondspecific wavelength band different from the first specific wavelengthband and acquiring the third image; the image separation means (forexample, the image separation unit 12) for acquiring a plurality ofseparate images based on the first image, the second image, and thethird image; and the passenger number determination means (for example,the passenger number determination unit 13) for determining the numberof passengers of the vehicle based on the plurality of separate images.According to such a passenger counting system, it is possible to reducenot only the reflection on the glass window but also the depth of thevehicle body portion of the vehicle, and thus, it is possible to savethe labor for the user to remove the reflection and the depth.

As above, the invention of the present application has been describedwith reference to the exemplary embodiments, but the invention of thepresent application is not limited to the above-described exemplaryembodiments. Various modifications that can be understood by the personskilled in the art can be made within a scope of the invention of thepresent application regarding the configuration and the details of theinvention of the present application. In addition, the invention of thepresent application may be obtained by combining the configurations ofthe respective exemplary embodiments as appropriate.

REFERENCE SIGNS LIST

10 First photographing unit

11 Second photographing unit

12 Image separation unit

13 Passenger number determination unit

14 Third photographing unit

30 First photographing means

31 Second photographing means

42 Image separation means

43 Passenger number determination means

100, 200 Passenger counting device

The invention claimed is:
 1. An image processing system comprising: atleast one memory storing instructions; and at least one processorcoupled to the at least one memory and configured to execute theinstructions to: acquire a first image which includes: a target objectilluminated by both of a first light and a second light, the secondlight being generated by a light source that emit light in a specificwavelength band; and an external object illuminated by the first lightbut not illuminated by the second light; acquire a second imagegenerated by photographing the second image within the same range as arange of the first image through a filter causing wavelengthdistribution of observed light for the second image to be different fromwavelength distribution of observed light for the first image; andgenerate: a third image in which intensity of a figure of the externalobject is raised as compared to the first image; and a fourth image inwhich intensity of a figure of the external object is reduced ascompared to the first image, wherein the at least one processor isconfigured to generate the third image and the fourth image byperforming an independent component analysis on the first image and thesecond image.
 2. The image processing system according to claim 1,wherein the at least one processor is further configured to: determinewhether a person is present in the fourth image; and determine a numberof persons in the target object based on the fourth image.
 3. The imageprocessing system according to claim 2, wherein the at least oneprocessor is configured to determine whether a person is present in thefourth image by performing detection of a specific part of a person, thespecific part being selected from: a nose; an eye; an arm; and a neck.4. The image processing system according to claim 1, wherein the atleast one processor is further configured to: perform face detection onthe fourth image, the face detection using a face detector which isconstructed in advance by performing machine learning using a pluralityof face images including at least any of frontal face images and faceimages photographed from a side; and determine a number of persons inthe object based on a result of the face detection.
 5. An imageprocessing method comprising: acquiring a first image which includes: atarget object illuminated by both of a first light and a second light,the second light being generated by a light source that emit light in aspecific wavelength band; and an external object illuminated by thefirst light but not illuminated by the second light; acquiring a secondimage generated by photographing the second image within the same rangeas a range of the first image through a filter causing wavelengthdistribution of observed light for the second image to be different fromwavelength distribution of observed light for the first image; andgenerating: a third image in which intensity of a figure of the externalobject is raised as compared to the first image; and a fourth image inwhich intensity of a figure of the external object is reduced ascompared to the first image, wherein the image processing methodcomprises generating the third image and the fourth image by performingan independent component analysis on the first image and the secondimage.
 6. The image processing method according to claim 5, furthercomprising: determining whether a person is present in the fourth image;and determining a number of persons in the target object based on thefourth image.
 7. The image processing method according to claim 6,comprising determining whether a person is present in the fourth imageby performing detection of a specific part of a person, the specificpart being selected from: a nose; an eye; an arm; and a neck.
 8. Theimage processing method according to claim 5, further comprising:performing face detection on the fourth image, the face detection usinga face detector which is constructed in advance by performing machinelearning using a plurality of face images including at least any offrontal face images and face images photographed from a side; anddetermining a number of persons in the object based on a result of theface detection.
 9. A non-transitory computer-readable storage mediumstoring a program that causes a computer to perform: acquiring a firstimage which includes: a target object illuminated by both of a firstlight and a second light, the second light being generated by a lightsource that emit light in a specific wavelength band; and an externalobject illuminated by the first light but not illuminated by the secondlight; acquiring a second image generated by photographing the secondimage within the same range as a range of the first image through afilter causing wavelength distribution of observed light for the secondimage to be different from wavelength distribution of observed light forthe first image; and generating: a third image in which intensity of afigure of the external object is raised as compared to the first image;and a fourth image in which intensity of a figure of the external objectis reduced as compared to the first image, wherein the program causesthe computer to perform: generating the third image and the fourth imageby performing an independent component analysis on the first image andthe second image.
 10. The non-transitory computer-readable storagemedium according to claim 9, wherein the program further causes thecomputer to perform: determining whether a person is present in thefourth image; and determining a number of persons in the target objectbased on the fourth image.
 11. The non-transitory computer-readablestorage medium according to claim 10, wherein the program causes thecomputer to perform: determining whether a person is present in thefourth image by performing detection of a specific part of a person, thespecific part being selected from: a nose; an eye; an arm; and a neck.12. The non-transitory computer-readable storage medium according toclaim 9, wherein the program further causes the computer to perform:face detection on the fourth image, the face detection using a facedetector which is constructed in advance by performing machine learningusing a plurality of face images including at least any of frontal faceimages and face images photographed from a side; and determining anumber of persons in the object based on a result of the face detection.